Finite group subschemes of abelian varieties over finite fields

Let A be an abelian variety over a finite field k. The k-isogeny class of A is uniquely determined by the Weil polynomial fA. For a given prime number ℓ≠chark we give a classification of group schemes B[ℓ], where B runs through the isogeny class, in terms of certain Newton polygons associated to fA. As an application we classify zeta functions of Kummer surfaces over k.